I have made some progress by using a script, as suggested: http://forums.adobe.com/message/2366871.
count = 0;
str = "";
while (count < 100)
str += "Circle #"+count+" on reader service card."+"\r";
app.selection.contents = str;
This script will insert the proper text lines into the selected Text Frame. The subsequent ones still have be manually threaded, but at least each is in a single Text Frame and I don't have to worry about spacing. If numbers change I can go to the first one and re-run the script.
Now if there were some way to dynamically thread Text Frames...
Nevermind. Paragraph numbering is easier, keeps track if I add or remove Text Frames, the only thing it doesn't do is let me control how they are numbered on a page. Numbering seems to start with first-created.
Now for my next challenge - inserting incrementing numbers elsewhere. Paragraph numbering works fine at the beginning of a line, but what if I need it at the end of a line? Each paragraph will contain different text, but I would like for each to end with an incrementing number.